Abstract

Exposure to fire and elevated temperatures is diachronically a significant decay factor, influencing the stability of structures. Cement and lime-based mortars have a different behavior when exposed at elevated temperatures, usually testified by the post-fire preservation state of historic and contemporary constructions. In this paper, the correlation of their properties is envisaged, in order to identify the key elements of their performance. To this direction, five compositions of cement and lime based mortars were manufactured and tested, after their exposure at 200oC, 400oC, 600oC, 800oC and 1000oC. The binders used concerned CEM I42.5Ν (C), hydrated lime (L) and natural pozzolan (P), while the systems applied regarded C, C:L (1:1), L, L:P (1:1) and L:P:C (1:0.8:0.2) (parts per weight). The aggregates used were natural of siliceous origin and their gradation varied from 0-4mm to 0-8mm. The B/A ratio was 1/2 by weight and the W/B ratio was adjusted in order to maintain workability around 15±1cm. The physico-mechanical properties of the specimens, were recorded before and after their exposure at the selected temperatures. From the evaluation of the results, it was concluded that the mortars’ behavior was different at the early temperature rate (up to 600oC) according to their type, whereas the results were more comparable at the extreme temperature level. Generally it was observed that although the initial strength of the lime-based mortars was low (1-4MPa), they presented a more stable and efficient performance at the elevated temperatures, rendering them probably more resistant at the first stages of fire actions. Cement- based mortars seemed to present a better performance at the highest temperatures of 800oC and 1000oC.